Moduleoptics-core-0.4.2Haskell2010

Optics.IxAffineFold

An IxAffineFold is an indexed version of an AffineFold. See the "Indexed optics" section of the overview documentation in the Optics module of the main optics package for more details on indexed optics.

Contents

Formation
Introduction
Elimination
Computation
Additional introduction forms
Additional elimination forms
Combinators
Monoid structure
Subtyping

Synopsis

type IxAffineFold
value iafolding
value ipreview
value ipreviews
value iafoldVL
value iatraverseOf_
value filteredBy
value iafailing
data An_AffineFold

Packageoptics-core-0.4.2
Exports9
LanguageHaskell2010
LicenceBSD-3-Clause
SourceIxAffineFold.hs

Formation

typetype IxAffineFold i s a = Optic' An_AffineFold (WithIx i) s a

Source#

Type synonym for an indexed affine fold.

Introduction

valueiafolding :: (s -> Maybe (i, a)) -> IxAffineFold i s a

Source#

Create an IxAffineFold from a partial function.

Elimination

valueipreview

:: (Is k An_AffineFold, HasSingleIndex is i)
=> Optic' k is s a
-> s
-> Maybe (i, a)

Source#

Retrieve the value along with its index targeted by an IxAffineFold.

valueipreviews

:: (Is k An_AffineFold, HasSingleIndex is i)
=> Optic' k is s a
-> i -> a -> r
-> s
-> Maybe r

Source#

Retrieve a function of the value and its index targeted by an IxAffineFold.

Computation

ipreview (iafolding f) ≡ f

Additional introduction forms

valueiafoldVL

:: forall (f :: Type -> Type). Functor f => (forall r. r -> f r) -> (i -> a -> f u) -> s -> f v
-> IxAffineFold i s a

Source#

Obtain an IxAffineFold by lifting itraverse_ like function.

aifoldVL . iatraverseOf_ ≡ id
aitraverseOf_ . iafoldVL ≡ id

Additional elimination forms

valueiatraverseOf_

:: (Is k An_AffineFold, Functor f, HasSingleIndex is i)
=> Optic' k is s a
-> forall r. r -> f r
-> i -> a -> f u
-> s
-> f ()

Source#

Traverse over the target of an IxAffineFold, computing a Functor-based answer, but unlike iatraverseOf do not construct a new structure.

Combinators

valuefilteredBy :: Is k An_AffineFold => Optic' k is a i -> IxAffineFold i a a

Source#

Obtain a potentially empty IxAffineFold by taking the element from another AffineFold and using it as an index.

Monoid structure

IxAffineFold admits a monoid structure where iafailing combines folds (returning a result from the second fold only if the first returns none) and the identity element is ignored (which returns no results).

Note: There is no isumming equivalent that returns an IxAffineFold, because it would not need to return more than one result.

There is no Semigroup or Monoid instance for IxAffineFold, because there is not a unique choice of monoid to use that works for all optics, and the (<>) operator could not be used to combine optics of different kinds.

valueiafailing

:: (Is k An_AffineFold, Is l An_AffineFold, HasSingleIndex is1 i, HasSingleIndex is2 i)
=> Optic' k is1 s a
-> Optic' l is2 s a
-> IxAffineFold i s a

Source#

Try the first IxAffineFold. If it returns no entry, try the second one.

Subtyping

datadata An_AffineFold

Source#

Tag for an affine fold.

Instances27Is, JoinKinds, IxOptic, ToReadOnly, ReadOnlyOptic, …

Is A_Getter An_AffineFoldDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
Is A_Lens An_AffineFoldDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
Is A_Prism An_AffineFoldDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
Is A_ReversedPrism An_AffineFoldDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
Is An_AffineFold A_FoldDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
Is An_AffineTraversal An_AffineFoldDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
Is An_Iso An_AffineFoldDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ A_Fold => JoinKinds A_Fold An_AffineFold kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ A_Fold => JoinKinds A_Traversal An_AffineFold kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ A_Fold => JoinKinds An_AffineFold A_Fold kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ A_Fold => JoinKinds An_AffineFold A_Traversal kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds A_Getter An_AffineFold kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds A_Lens An_AffineFold kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds A_Prism An_AffineFold kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds A_ReversedPrism An_AffineFold kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds An_AffineFold A_Getter kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds An_AffineFold A_Lens kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds An_AffineFold A_Prism kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds An_AffineFold A_ReversedPrism kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds An_AffineFold An_AffineFold kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds An_AffineFold An_AffineTraversal kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds An_AffineFold An_Iso kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds An_AffineTraversal An_AffineFold kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
k ~ An_AffineFold => JoinKinds An_Iso An_AffineFold kDefined in optics-core-0.4.2 · Optics.Internal.Optic.Subtyping
(s ~ t, a ~ b) => IxOptic An_AffineFold s t a bDefined in optics-core-0.4.2 · Optics.Indexed.Core
(s ~ t, a ~ b) => ToReadOnly An_AffineFold s t a bDefined in optics-core-0.4.2 · Optics.ReadOnly
type ReadOnlyOptic An_AffineFold = An_AffineFoldDefined in optics-core-0.4.2 · Optics.ReadOnly